title: Safety and efficacy of motor mapping utilizing short pulse train direct cortical stimulation.
abstract: OBJECTIVE
  A major goal of intracranial surgery is to maximize resection while minimizing neurological morbidity, particularly motor dysfunction. Direct cortical stimulation (DCS) is a common intraoperative adjunct used to identify functional motor cortex. In this study, we report on the safety/efficacy of short pulse train DCS (direct cortical stimulation motor-evoked potential, dcMEP) for motor mapping and monitoring during intracranial surgery.
  
  
  METHODS
  A retrospective analysis of 29 patients undergoing elective craniotomy for lesions near the motor cortex was performed. dcMEP mapping (40-120 V, 500-1,000 Hz, 5-9 pulses/s, 1- to 3-ms interstimulus interval, monopolar, 50-μs pulse width) was performed either alone (n = 29) or in addition to standard DCS (n = 6). Outcome measures were positive MEPs and the presence of seizures during stimulation. dcMEP-based continuous corticospinal tract (CST) monitoring was also performed. Changes in stimulation threshold and new postoperative neurological deficits were recorded.
  
  
  RESULTS
  dcMEP mapping success was 96% and was not affected by preoperative motor status. Intraoperative seizure rates for dcMEP were 3% and were not related to preoperative seizure status. CST monitoring success rate was 96%, and changes in stimulation threshold were predictive of new permanent motor deficits.
  
  
  CONCLUSIONS
  dcMEP is an effective method for mapping motor function and may prove useful for continuous CST monitoring.
authors.affiliation: Department of Neurological Surgery, University of California, San Francisco, Calif., USA.
authors.forename: Matthew C
authors.initials: MC
authors.lastname: Tate
authors.forename: Lanjun
authors.initials: L
authors.lastname: Guo
authors.forename: Jennifer
authors.initials: J
authors.lastname: McEvoy
authors.forename: Edward F
authors.initials: EF
authors.lastname: Chang
mesh_terms: D000328:Adult; D000368:Aged; D001931:Brain Mapping / Q000009:adverse effects* / Q000379:methods; D001932:Brain Neoplasms / Q000503:physiopathology / Q000601:surgery; D004558:Electric Stimulation / Q000009:adverse effects* / Q000379:methods; D019054:Evoked Potentials, Motor / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000503:physiopathology / Q000601:surgery*; D011712:Pyramidal Tracts / Q000503:physiopathology / Q000601:surgery; D012189:Retrospective Studies